Helical heater for tubes, &amp;c.



J. I. AYER.

' HBLIGAL HEATER FOR TUBES, Mr.

APPLICATION FILED NOV. 25, 1010.

995, 51, PatentedJune 13,1911.

A2 if'i'iiihi ll- Mme/5669: ITUU,@TO%IOTU ACHU' SETT, ASSIGNOR TO SIMPLEX ELECTRIC AS ACHUSETTS, A CORPORATZON OF rmss mum IVIAS- 'bATING i'JQ'M'PANY, SACI-IUSIETTS.

Jmie T &c.

tent.

Serial No. 594,129.

FELICAL HEATER FOB. TUBES,

Qpecification of Letters Pa application flied November 25. 1910.

2. Vd W00 90 .1 MW. Tx

i 0 rn (DH sing; tube being shown ve View;

a perspecii thereof.

plates 1 of mica, th

-ei ph 1' SGllC oun Wi iii pen i; n t i in n insulating n1 sks, at the 4: spaced apzi Lem? e 5.

sheets or suifiabio f :1 proper f suziily as (ii in ections The. resistance a :1 spiral W11 nice 10 1y be GiiliiQl form. 101' start at 8. meme next disk 5 in niine'nic nii OiiM/Ciy be- 7( rind the viiioh it will irectiy behind a iobe '7, and in .I the Wire is .1030 give h nd altertor,

6 applied 9i s 1 so Lhat the- .36 e and. 12.

isk

in that the the disk lnbes i uniform W n ilfijil- 8( W for an Lil 1 9." tube may 1( ZLZICQ, tin: contain be bent to a circular, spiral or any other desired form and there still be no possibility of a short circuit between different portions of the coil nor any appreciable approach between adjacent portions thereof or of any portion to the tube. There is thus provided a construction wherein the insulating elements while insuring proper insulated relat-ion between the several parts or the coil and between the coil and the tube, at the same time in no Way interfere with the radiation of heat from the coil to the tube or from the tube to the object to be heated, while also permitting currents of air to pass freely through the device, thus effecting transfer of heat by convection as well as conduction and radiation. I

It is to be understood that my invention in its broader aspect contemplates the construction ofthe novel arrangement of insulators or insulating means in the spiral, designed for use in tubes or containers not necessarily round. For instance, the tube or container may be of square, elliptical, hexagonal, or other cross-section; in such case the spiral resistance element or the insulating disks, or both, would preferably be formed to follow the form of the walls of the duct or channel, whatever shape its cross-section might be, to lie as nearly parallel as possible therewith. Further, it is obvious that while in the preferred construction shown,-round wire is employed, formed into a regular spiral, as the resistance element, it is equally within the scope of the invention with the necessary slight changes in the form of disk, to modify the form of the coil within wide limits, or to change the cross-section of the resistance element from a round to an angular wire or ribbon or to any other shape which might be found desirable, these being merely minor changes that can obviously be carried out without departing from the spirit of the invention.

Having described my invention, what I claim as new and desire to secure by Letters Patent is,

1. An electric heater member comprising a spiralresistance element, insulating plates disposed between turns of said resistance element, and .held in [place thereby, said plates projecting radially outward adjacent the several turns of the resistance element beyond the same, about the circumference thereof to provide an insulatin protector around the periphery of the resistance element and permit free transmission of heat from said resistance element both -by radiation and air convection.

2. An electric'heater member comprising a continuous spiral resistance element, insulation disposed between turns of said resistance element and projecting radially beyond the same adjacent the respective spiral turns, and a tube fitted to the periphery of said insulation, and held thereby in spaced apart relation to said resistance element whereby distribution of heat by air convection from said resistance element is permitted.

3. An electric heater member, comprising a continuous spiral resistance element, and insulating plates having cut out portions disposed between turns thereof, each turn crossing a plate at its out outportion.

4. An electric heater member, comprising a continuous spiral resistance element, in-

sulating plates with cut out portions disposed between turns thereof, and projecting from the periphery thereof, each coil crossing a plate at a cut out portion thereof.

5. An electric heater member, comprising a resistance coil, insulating plates having spaced apart lobes projected between turns of said coil, said coil engaging alternate lobes on opposite sides.

6. An electric heater member, comprising a resistance coil, and insulatin plates having a series of lobes projected therethrough, the coil engaging opposite sides of the alternate lobes of each successive plate.

7. An electric heater member, comprising a resistance coil, insulating plates disposed between turns of the coil and constructed to permit the coil to pass alternately from one side to the other thereof at determinate spaced apart points.

8. An electric heater member, comprising a resistance coil, insulating disks having cut out portions to form three equidistant lobes projected between turns ofsaid coil and beyond the periphery thereof, the coil passing on opposite sides of successive lobes.

9. An electric heater member, comprising a resistance coil,, insulating disks having portions cut out to form lobes projected between turns of said coil beyond the periphery thereof, to permit the coil to pass alternately from one side to the other of successive lobes, and a conductive casing fitted over said disks. I

10; An electric heater member, com rising a resistance coil, insulating disks aving portions cut away to form equi-distantlobes, and having the coil intertwined around said lobes, said lobes projecting beyond the coil, a return conductor rod connected to an end of said coil extending throu h said disks, and an inclosing heat conductive tube fitted over said disks.

11. An electric heater member comprising a continuous resistance spiral, and insulating plates held in fixed operative osition by engagement With the turns of said spiral, each plate having different portions between different turns.

12. An electric heater member comprising a continuous resistance spiral, insulating plates, held in fixed operative position by engagement with the turns of said spiral, name to this specification, in the presence of each plate having different portions betwo SHbSCIIbIIIg wltnesses. tween dliferent' turns, sand plates extendmg peripherally beyond the turns of the spiral, v JAMES AYER' 5 anplan inclosing heat conductive tube fitted Witnesses: over said plates. J DORA A. Pnoc'ron I1 testimony whereof, I have signed my ELIZABETH M. CONLIN. 

